Dave,
About 20 years ago, I used double, No.10 Biscuits to join 75 mm square legs to 70mm x 30mm stiles and stretchers. The six foot bench was for a Coronet Major lathe/combo machine. A heavy beast made from solid cast iron and steel. That is on castors that are soft and too small, so it's had a lot of mauling about over a rough concrete floor. It's still tight and in use now as a temporary mitre saw bench. if I made it again with biscuits, I would go up to No. 20s. But the replacement is going to have through, wedged, M & Ts. Mainly because I feel like doing them!
I think for your sander and Bench drill, biscuits would be okay. If you are nervous, maybe add some Kreg screws; or suitable ordinary screws if you don't have a Kreg Jig. On the other hand you could make the cabinet frame and panel. That would last you for ever. But I think you'll be okay with biscuits.
HTH
